Reproducing head with spin-torque oscillator, and magnetic recording and reproducing apparatus

1. A reproducing head with a spin-torque oscillator, the head comprising: the spin-torque oscillator having a first surface facing a magnetic recording medium, the spin-torque oscillator used to detect a magnetic field from the magnetic recording medium; and a pair of shield parts each having a second surface facing the magnetic recording medium, the spin-torque oscillator being arranged between the shield parts, wherein a distance between the second surface and the magnetic recording medium is shorter than a distance between the first surface and the magnetic recording medium.

2. The head according to claim 1 , further comprising an insulating layer formed in a portion enclosed by the pair of shield parts, the insulating layer having a third surface facing the magnetic recording medium, wherein the third surface is flush with the second surface.

3. The head according to claim 1 , wherein the spin-torque oscillator comprises a multilayered structure including an oscillation layer having rotatable magnetization.

4. The head according to claim 3 , wherein the oscillation layer is arranged in a center between the pair of shield parts.

5. The head according to claim 3 , further comprising a bias magnetic field source configured to apply a bias magnetic field to the oscillation layer.

6. The head according to claim 5 , wherein the oscillation layer has a first axis defined in a longitudinal direction of a film surface of the oscillation layer, and a second axis defined in a lateral direction of the film surface, and is formed such that the second axis is parallel to a direction in which a medium magnetic field generated from the magnetic recording medium acts on the oscillation layer.

7. A magnetic recording and reproducing apparatus comprising the reproducing head with the spin-torque oscillator according to claim 1 , and the magnetic recording medium.